1. Field of the Invention
The present invention generally relates to a gastrointestinal diagnostic capsule that includes an encapsulated expandable foam material introduced through the oral cavity and through the esophagus into the stomach with the capsule being dissolved by the temperature and the moisture conditions encountered in the stomach so that the foam block or cube can expand and be withdrawn through the gastroesophageal junction and up through the entire esophagus to obtain specimen material for diagnostic procedures for early detection of gastroesophageal cancer. The capsule and encapsulated expandable body or block of foam material which has been reduced in volume before encapsulation includes a flexible cord connected thereto and is preferably introduced on the end of a nasogastric tube, gastroscope or other appropriate stylus device to enable accurate positioning of the capsule after which the introducer or nasogastric tube may be withdrawn so that when the abrasive foam body or block has expanded in the stomach, it may be withdrawn through the gastroesophageal junction and up through the entire esophagus with the large exposed pore surface area of the abrasive foam block obtaining cellular specimens for subsequent processing and cytology to enable ready detection of gastroesophageal cancer.
2. Information Disclosure Statement
Esophageal cancer, once established, is almost uniformly fatal. Accordingly, early detection of gastroesophageal cancer is quite important in altering the lethality of the disease and it is generally assumed that unless esophageal cancer is detected at the epithelial or surface stage, the lethality cannot be altered. Techniques for early diagnosis of esophageal cancel involve the use of frequent endoscopy which has substantial limitations due to its reliance on inspection or random biopsy. Some efforts have been made to obtain specimen material for cytology by utilizing an inflatable balloon covered with a fishnet type of material which is stretched when the balloon is inflated so that it will abrade the esophagus during withdrawal which necessitates the introduction of the balloon into the stomach or esophagus when uninflated and subsequently the balloon must be inflated with extreme care being necessary to monitor the degree of inflation so that an appropriate abrading action on the esophagus can be obtained when the inflated balloon is withdrawn without the balloon being over inflated and causing esophagus trauma. Moreover, the fishnet pore surface area is substantially reduced due to the relatively large void spaces between the strands of the fishnet.
The incidence of gastroesophageal cancer varies considerably in different geographical areas. In those areas having a very high incidence of esophageal cancer such as the Far East, Scandinavia and to some extent in Puerto Rico, frequent endoscopy is performed in an attempt to accomplish early detection and postoperative monitoring of esophageal cancer. While the incidence of esophageal cancer in the United States is relatively low, esophageal cancer is everywhere considered almost uniformly lethal, due partly to proximity of the esophagus to vital structures that cannot be readily resected in a cancer operation and also being partly due to failure of early detection. Thus, while early detection and monitoring is recognized as a necessity in the reduction of lethality of esophageal cancer, the techniques for such detection remain relatively primitive and have not been effective in early detection of the disease except as cited with the fishnet balloon device.